﻿#define _CRT_SECURE_NO_WARNINGS 1

//编程初学者入门训练第三十一题
//BC33 计算平均成绩
//https://www.nowcoder.com/practice/30a28eb88c3f4e87be1a5b397ddd6fe2?tpId=107&tqId=33314&rp=1&ru=/exam/oj/ta&qru=/exam/oj/ta&sourceUrl=%2Fexam%2Foj%2Fta%3FtpId%3D107&difficulty=undefined&judgeStatus=undefined&tags=&title=

#include <stdio.h>

int main() {
    int num1 = 0;
    int num2 = 0;
    int num3 = 0;
    int num4 = 0;
    int num5 = 0;

    scanf("%d %d %d %d %d", &num1, &num2, &num3, &num4, &num5);

    printf("%.1f", (num1 + num2 + num3 + num4 + num5) / 5.0);

    return 0;
}